Cell Core C continues FSHD biomaterials acquisition to support Projects 1, 2, and 3, as well as the FSHD research community with our cell repository distribution program. A new focus on FSHD families with nonmanifesting carriers of the genetic signature will expand on the usefulness of our repository by providing DNA from blood, muscle biopsy tissue and cells derived from biopsies for investigating modifiers of FSHD pathology. Subjects recruited into the program with confirmatory genetic testing will be asked to participate and give informed consent. Biceps muscles, which tend to be affected early in FSHD pathology, will be biopsied and coded to mask patient identity (Aim 1). Biopsy material will be distributed for histology (Aim 2), RNA screening (Proj. 2, Aim 1), which will inform xenograft studies (Proj. 3, Aims 1&2), and fiber-based xenografts (Proj. 3, Aim 1). Primary muscle cells will be isolated (Aim 2) and expanded for banking and distribution (Aim 3); CD56+ muscle cells will be provided to Center investigators for RNA screening (Proj. 2, Aim 1), study of the epigenetic regulation of DUX4-fl (Proj. 2, Aim 2), the development of antisense morpholino drugs (Proj. 2, Aim 3) and for cell-based xenografts (Proj. 3, Aim 2). Cell availability is advertised on the FSH Society and Center websites and at the annual FSHD Research International Consortium Meeting. Finally, the Bioinformatics Core (Aim 4) will be responsible for managing databases of integrated clinical and experimental data, and provide bioinformatic support to whole genome/exome studies (Proj. 1, Aim 2), whole transcriptome sequencing studies (Proj. 2, Aim 1 & 3), biomarker validation (Proj. 2, Aim 1), validation of cell-based xenografts (Proj. 3, Aim 2), evaluation of AAV and morpholino antisense drugs (Proj. 2 Aim 3 and Proj. 3 Aims 1&2) and developmental screening for DUX4 target genes (Proj. 3, Aim 4).